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Optimization of electrically active magnetic nanoparticles as accurate and efficient microbial extraction tools.

Cloutier BC, Cloutier AK, Alocilja EC - Biosensors (Basel) (2015)

Bottom Line: EAMNP concentrations of 1.0 and 0.5 mg/mL provided optimal analytical sensitivity and analytical specificity.The entire IMS procedure requires only 35 min, and antibody-conjugated MNPs show no decline in performance up to 149 days after conjugation.This analytically sensitive and specific extraction protocol has excellent longevity and shows promise as an effective extraction for multiple electrochemical biosensor applications.

View Article: PubMed Central - PubMed

Affiliation: Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 275 Slappy Drive, Hamilton, GA 31811, USA. barbara.cloutier@us.army.mil.

ABSTRACT
Food defense requires the means to efficiently screen large volumes of food for microbial pathogens. Even rapid detection methods often require lengthy enrichment steps, making them impractical for this application. There is a great need for rapid, sensitive, specific, and inexpensive methods for extracting and concentrating microbial pathogens from food. In this study, an immuno-magnetic separation (IMS) methodology was developed for Escherichia coli O157:H7, using electrically active magnetic nanoparticles (EAMNPs). The analytical specificity of the IMS method was evaluated against Escherichia coli O55:H7 and Shigella boydii, and was improved over previous protocols by the addition of sodium chloride during the conjugation of antibodies onto MNPs. The analytical sensitivity of the IMS method was greatest when a high concentration of antibodies (1.0 mg/mL) was present during conjugation. EAMNP concentrations of 1.0 and 0.5 mg/mL provided optimal analytical sensitivity and analytical specificity. The entire IMS procedure requires only 35 min, and antibody-conjugated MNPs show no decline in performance up to 149 days after conjugation. This analytically sensitive and specific extraction protocol has excellent longevity and shows promise as an effective extraction for multiple electrochemical biosensor applications.

No MeSH data available.


Related in: MedlinePlus

Capture efficiency (log10 of CFU/mL captured/ log10 of CFU/mL present) of each E. coli O157:H7 sakai strain captured in IMS, using Mab-EAMNPs, at varying days from conjugation stored at refrigerated temperatures from (1–5 days, n = 184; 6–130 days, n = 31; 130 to 149 days, n = 37). There was no statistical difference between any of the three groups.
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biosensors-05-00069-f006: Capture efficiency (log10 of CFU/mL captured/ log10 of CFU/mL present) of each E. coli O157:H7 sakai strain captured in IMS, using Mab-EAMNPs, at varying days from conjugation stored at refrigerated temperatures from (1–5 days, n = 184; 6–130 days, n = 31; 130 to 149 days, n = 37). There was no statistical difference between any of the three groups.

Mentions: Longevity of the Mab-EAMNP solutions was also evaluated by one-way ANOVA and independent two-tailed T-tests. With the previously reported method of conjugating antibodies onto EAMNPs [21,22], long-term storage of Mab-EAMNP solutions (at 4 °C) resulted in poorer IMS performance. This observation led to Hypothesis 1d, that the number of days elapsed since conjugation of antibodies onto EAMNPs will affect the analytical sensitivity and specificity of IMS. One-way ANOVA and independent two-tailed T-tests were performed on the mean concentration of captured cells (log10 of CFU/mL) for all three bacteria, comparing the experimental results obtained from Mab-EAMNP solutions ranging in age from 0 to 149 days (Figure 6). Regardless of which statistical test was applied, no significant difference was observed in IMS capture of any of the three bacteria. Based on these statistical results, Hypothesis 1d is retained. Days elapsed since conjugation of antibodies onto MNPs (stored at 4 °C), from 0 to 149 days, has no effect on analytical sensitivity or specificity.


Optimization of electrically active magnetic nanoparticles as accurate and efficient microbial extraction tools.

Cloutier BC, Cloutier AK, Alocilja EC - Biosensors (Basel) (2015)

Capture efficiency (log10 of CFU/mL captured/ log10 of CFU/mL present) of each E. coli O157:H7 sakai strain captured in IMS, using Mab-EAMNPs, at varying days from conjugation stored at refrigerated temperatures from (1–5 days, n = 184; 6–130 days, n = 31; 130 to 149 days, n = 37). There was no statistical difference between any of the three groups.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384083&req=5

biosensors-05-00069-f006: Capture efficiency (log10 of CFU/mL captured/ log10 of CFU/mL present) of each E. coli O157:H7 sakai strain captured in IMS, using Mab-EAMNPs, at varying days from conjugation stored at refrigerated temperatures from (1–5 days, n = 184; 6–130 days, n = 31; 130 to 149 days, n = 37). There was no statistical difference between any of the three groups.
Mentions: Longevity of the Mab-EAMNP solutions was also evaluated by one-way ANOVA and independent two-tailed T-tests. With the previously reported method of conjugating antibodies onto EAMNPs [21,22], long-term storage of Mab-EAMNP solutions (at 4 °C) resulted in poorer IMS performance. This observation led to Hypothesis 1d, that the number of days elapsed since conjugation of antibodies onto EAMNPs will affect the analytical sensitivity and specificity of IMS. One-way ANOVA and independent two-tailed T-tests were performed on the mean concentration of captured cells (log10 of CFU/mL) for all three bacteria, comparing the experimental results obtained from Mab-EAMNP solutions ranging in age from 0 to 149 days (Figure 6). Regardless of which statistical test was applied, no significant difference was observed in IMS capture of any of the three bacteria. Based on these statistical results, Hypothesis 1d is retained. Days elapsed since conjugation of antibodies onto MNPs (stored at 4 °C), from 0 to 149 days, has no effect on analytical sensitivity or specificity.

Bottom Line: EAMNP concentrations of 1.0 and 0.5 mg/mL provided optimal analytical sensitivity and analytical specificity.The entire IMS procedure requires only 35 min, and antibody-conjugated MNPs show no decline in performance up to 149 days after conjugation.This analytically sensitive and specific extraction protocol has excellent longevity and shows promise as an effective extraction for multiple electrochemical biosensor applications.

View Article: PubMed Central - PubMed

Affiliation: Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 275 Slappy Drive, Hamilton, GA 31811, USA. barbara.cloutier@us.army.mil.

ABSTRACT
Food defense requires the means to efficiently screen large volumes of food for microbial pathogens. Even rapid detection methods often require lengthy enrichment steps, making them impractical for this application. There is a great need for rapid, sensitive, specific, and inexpensive methods for extracting and concentrating microbial pathogens from food. In this study, an immuno-magnetic separation (IMS) methodology was developed for Escherichia coli O157:H7, using electrically active magnetic nanoparticles (EAMNPs). The analytical specificity of the IMS method was evaluated against Escherichia coli O55:H7 and Shigella boydii, and was improved over previous protocols by the addition of sodium chloride during the conjugation of antibodies onto MNPs. The analytical sensitivity of the IMS method was greatest when a high concentration of antibodies (1.0 mg/mL) was present during conjugation. EAMNP concentrations of 1.0 and 0.5 mg/mL provided optimal analytical sensitivity and analytical specificity. The entire IMS procedure requires only 35 min, and antibody-conjugated MNPs show no decline in performance up to 149 days after conjugation. This analytically sensitive and specific extraction protocol has excellent longevity and shows promise as an effective extraction for multiple electrochemical biosensor applications.

No MeSH data available.


Related in: MedlinePlus